Failure Analysis of Graphene Sheets with Multiple Stone-Thrower-Wales Defects Using Molecular- Mechanics Based Nonlinear Finite Element Models

Abstract

Experimental studies show that Stone-Thrower-Wales (STW) defects generally exist ingraphene sheets (GSs) and these defects considerably affect the fracture strength of GSs.Thus, prediction of failure modes of GSs with STW defects is useful for design of graphenebased nanomaterials. In this paper, effects of multiple STW defects on fracture behavior ofGSs are investigated by employing molecular mechanics based nonlinear finite element models.The modified Morse potential is used to define the non-linear characteristic of covalentbonds between carbon atoms and geometric nonlinearity effects are considered in models.Different tilting angles of STW defects are considered in simulations. The analysis resultsshowed that the fracture strength of GSs strongly depends on tilting angle of multiple STWdefects and the STW defects cause significant strength loss in GSs. The crack initiation andpropagation are also studied and brittle failure characteristics are observed for all samples.The results obtained from this study provide some insights into design of GS based-structureswith multiple STW defects.